Process for the destructive hydrogenation of high boiling-point hydrocarbons with the formation therefrom of hydrocarbons having a lower boiling-point



R. H. GRIFFITH PROCESS FOR THE DESTRUCTIVE HYDROGENA March 12, 1935.1,994,277 TION OF HIGH BOILING POINT HYDROCARBONS WITH THE FORMATIONTHEREFROM OF HYDROCARBONS HAVING A LOWER BOILING POINT Filed Jan. 1932 2Sheets-Sheet 1 I a 6 I M 4 E, HV/

IOO YGRAMS OF TAR I GRAMS C52 ADDED PER March 12, R H GR|FF|TH 1,994,277

PROCESS FOR THE DESTRUCTIVE HYDROOENATION OF HIGH BOILING POINTHYDROCARBONS WITH THE FORMATION THEREFROM OF HYDROGARBONS HAVING A LOWERBOILING POINT Filed Jan. 2, 1932 2 Sheets-Sheet 2 Mam/012 Mae/waifPatented Mar. 12,1935 7 fUNlTED' STATES PATENT oFricE Roland HallGriffith, London, England, assignor to lhe Gas Light & Coke Company,London, England, a British company 7 Application January 2, 1932, SerialNo. 584,412 In Great Britain January 12, 1931 I 13 Claims. (Cl. 19653)This invention relates to processes for the destructive hydrogenation ofhigh boiling-point hydrocarbons and derivatives ,thereof'by treatmentwith hydrogen, or other reducing gases such'as water gas, at an elevatedtemperature and pressure, with the formation of hydrocarbons having alower boiling point than the boiling point of the hydrocarbon or.derivative treated. Such processes are hereinafter referred to asprocesses of the type described.

Instances of high boiling-point hydrocarbons the treatment of which iscontemplated in this invention include coal tar, natural petroleum,asphalt, bitumen, heavy oils and oil fractions produced from thesesubstances. The hydrocarbon derivative may be a phenolic body.

It is known to assist'the reaction in destructive hydrogenationprocesses of the type described by the presence in the reaction sphereof a molybdenum catalyst and a promoter therefor. I a

It is also known to aid the reaction in such processes by employingappropriate proportions of hydrogen sulphide along with the molybdenumcatalyst and promoter.

We have found, on investigatingthe use-of a promoter with a molybdenumcatalyst in processes of destructive hydrogenation of high boiling-pointhydrocarbons, that ii a curve of catalyst-activity be plotted, theordinates of this curve representing the activity of the catalyst interms of percentage yield of hydrogenation product boiling below a giventemperature, for

example 180 (3:, and the abscissa of the curve representing the atomicproportion of promoter element to molybdenum used in the process, suchcurve has in it'anacute peak or peaks. The presence of these peaksindicates that'certain closely defined proportions of promoter tocatalyst give markedly better results in yield of hydrogenation productthan ratios elsewhere on the curve, and the broad idea of selecting andusing a peak ratio of promoter to catalyst in destructive hydrogenationprocesses in which a molybdenum catalyst is used aided by a promoter, isdescribed and claimed in United States patent specification Serial No.501,998.

We have now discovered that peaks in the catalyst-activity curve .occur'with varying proportions of promoter also in'cases where the reaction isassisted by the joint action of..a ,molybdenum catalyst, apromotertherefor and appropriate proportions of hydrogen sulphide, sulphur or asubstance yielding hydrogen sulphide under the conditionsof thereaction, and

further th'atthe peaks occur in the same positions in the curve.

According to the present invention, therefore,

a'process of the type described for the destructive hydrogenation ofhigh-boiling point hydrocarbons or derivatives thereof in the presenceof a molybdenum catalyst, a promoter therefor, and hydrogen sulphide,sulphur or a substance yielding hydrogen sulphide under the conditionsof the reaction, is characterized by the selection and use of apeak-ratio of promoter to catalyst; that, is to say, a ratio of promoterto catalyst which is within the peak or one of the peaks of thecatalyst-activity curve hereinbeiore referred to. a

In most cases the curve comprises two peaks, and the position of thesecond peak is independent of the temperature employed inthe process andalso of the initial hydrocarbonmaterial submitted to the treatment.Preferably therefore, the ratio used of promoter to catalyst is theoptimum ratio of the second peak of the catalyst-activitycurve.

In cases where the catalyst-activity curve comprises two peaks, thatportion of the curve which lies between the peaks generally represents adepression of activity; that is to say, the use of ratios betweenthe twopeaks of the curve generally results in a definite depression ofactivity of the catalyst below the activity the catalyst would have ifit were used alone, and is, therefore, positively disadvantageous.

The free hydrogen sulphide should be-present in the criticalproportions, relatively to the quan tity of initial material treated,which ensure the highest yield. If too much sulphur or hydrogen sulphidebe present, certain undesirable reactions tend to set in. An undueexcess of sulphur or hydrogen sulphide may alsore'sult in excessivesulphurization of thehydrogenation of the sulphur appears to be to forma molybdenum sulphide (i. e. in the event of metallic molybdenum beingused in the process), and it i is the excess of hydrogensulphide overthe sulphur in combination with the molybdenum that operates to enhancethe activity, of the catalyst, at anyrate to. the remarkable degree thatis characteristic of the present invention. The

'imately 5-8: 100.

actual proportion in any given case depends upon the nature and inparticular the chemical constitution of the initial material treated,but is readily determinable by a simple preliminary test.

The hydrogen sulphide may either be introduced as such into the reactionsphere, or it may be formed in situ therein; Inthe latter case,elemental sulphur may be introduced into the reaction sphere to combinewiththe hydrogen therein, or conveniently carbonbisulphide may be mixedwith the tar or other initial material to be treated; or again therequisite quantity of sulphur may be derived from the initial materialitself. In some cases the initial materialmay be found to be too rich inavailable sulphur, in which event thesaidmaterial may be blended withother initial material less rich in sulphur or sulphur-free.

The molybdenum catalyst may either consist of molybdenum in theelemental form, or of an appropriate molybdenum compound, for example,molybdic acid. 7

, Similarly, the promoter may either be in the elemental form, or in theform of a suitable compound, for example, an oxygen compound or asulphide of the element. In this connection it ,is to be understood thatthe expression promoter element used in this specification isintended-to connote, in the case of a compound, the metal or otherelement with which the oxygen, sulphur, or other component ofthecompound is combined. Various promoter elements have been found to givesatisfactory results in the process. Preferably, however, the promoterelement is one of the lighter metals,'alkaline earth metals, metalloids,or solid non-metallic elements. More specifically, the followingpromoter elements have been found to give good results:--silicon,

boron, lithium, phosphorus, calcium. Of these specific promoters,silicon, boron and phosphorus appear to be the mostsatisfactory.

' The use as the promoter of sulphur'as such is excluded from the scopeof the invention, as sulphur is a substance which per se will notoperate as a promoter in the process.-

As previously indicated herein, it is preferable to use a ratio ofpromoter element to the molybdenum which is within the second peak-ratiorange of the catalyst-activity curve. In the case of silicon, the secondpeak-ratio range is approx- In the case of boron, it is approximately7-l0z100. .Ihe corresponding peak}- ratio changes in the case oflithium, phosphorus and calcium are respectively :7-'7.5 100, 4-4.5

and 7.5-7.8:100.

The approximate values of the peak-ratios of promoter to molybdenum forthe preferred promoters mentioned above are indicated on the graphsaccompanying United States Patent No. 1,938,328.

In the drawings Figure 1 illustrates more or less approximately typicalcurves for the yield of spirit when a standard low temperaturecarbonization tar is subjected to destructive hydrogenation in thepresence of molybdenum catalyst alone, and in' the presence ofmolybdenum catalyst promoted by various promoters and'with the additionof various amounts of sulphur in the form of carbon bisulphide. .Theordinates represent the percentageof distillate boiling below "180 C.and the abscissa: represent the num- 'ber of grms. of carbon bisulphideadded. to 100 guns. of the tar (previously topped'to 200" C.).

correctly promotedmolybdenum with the tratively indicated 'in Figure 1accompanying .water and 130 cos. of an creasing amounts of carbonbisulphide are added to a molybdenum catalyst; curve II represents thevariation in the percentage of spirit when the carbon bisulphide isadded to a molybdenum catalyst-silicon promoter in which the ratio ofsilicon to molybdenum is within one of the peakratio ranges abovereferred to; andcurve III similarly represents the variation in theyield of spirit when the molybdenum catalyst is promoted with phosphorusand the ratio of'phosphorus to molybdenum is likewise within, one of thepeak-ratio'ranges above referred to.

It will be clear from the curves that there is an optimum amount ofcarbon bisulphide which 7 when added to the molybdenum catalyst alone ormolybdenum catalyst mixed with a promoter gives a maximum yield ofspirit-from tar, and it will further benoticed that the yields of spiritusing molybdenum catalyst alone with a I certain amount of carbonbisulphide are always less than the yields of spirit when" employingsame amount of carbon bisulphide. It is a featureof this inventiontherefore that not only-is the ratio of promoter. to molybdenum withinthe peak ratio range orone of the peak ratio ranges hereinbeforereferred 'to, but'also 2c I V thatthe process of the type described forthe destructive hydrogenation'of high boiling point 1 out with theoptimum or approximately the optimum proportion of hydrogen 'sulphiddsul phur or a substance yielding hydrogen sulphide under theconditions-of the :reaction as illusthis specification. 1 1

One type of apparatus suitable for carrying the present invention intoeffect 'is'shown in diagrammatic form in Figure .2 in which 1 is areservoir for the high-boiling hydrocarbon (for example an oil or tar)to be treated, 2fis a pump'delivering the oil or tar to the electricallyheated catalyst vessel 5 where it reacts in the presence of a substanceyielding hydrogen sulphide under the conditions of the reaction wi thhydrogenating as delivered by a compressor- 3 50 from an inletpipe 4. 7

After leaving the catalyst vessel5the products of the reaction pass intoa condenser 6 and thence into separators 7 and 9. Gas leaves the Vseparators-throughpipes 8 andll whileliquid is drawn off from the systemthrough pipe 10. The following. examples of the invention will now bedescribed. 3

Example 1 sure of atmospheresiin the presencev of -10 grams of sulphurand IOgrams of a catalystipro- 7 moter mixture consisting of molybdicacid an'dsilicanin the atomic MozSi ratio of. 100:5.5.

hydrocarbons and derivatives thereof is carried 1 5 The-hydrogenationproduct comprised 19 cgcshof' '7 comprised 22 c. cs.v of water and 0.cs. of

an oil, 53% of which boiled below 180 C.

In Example 1, the promoter proportion was at the optimum point of thesecondpeak of the catalyst-activity curve for silicon promoters. InExample 2, the promoter proportion was at the optimum point of the firstpeak ofsaid curve.

, Example 3 The same'tar again was treated under conditions similar tothose in Examples 1 and-2, but

in this case, the atomic MozSi ratio was 100} 4.4. This ratio is locatedon the catalyst-activity curve for silicon, at a point between the firstand second peaks thereof and the hydrogenation product comprised 147 0.es of an oil, of which only 44% boiledbelow 180 C. This'example,

as will beappreciated, illustrates the harmful.

effect of employing a ratio of' promoter'to catalyst which is not in oneor other of the peak ratio ranges of the catalyst-activity curve.

Example 4 The same low-temperature tar was treated under conditionssimilar to those obtaining in the previous examples, but with amolybdenum-boron catalyst promoter mixture, in which the atomic Mo:Bratio was 100:8.7. The product comprised 0. cs. of an oil, 54% of whichboiled below C.

It is to be understood that the expression peak-ratio proportions isused in the following statement of claim to denote proportions ofcatalyst and promoter within the peak portion of the catalyst-activitycurve hereinbefore referred to with reference to United States Patent1,938,328. Further, it is to be understood that the peak-ratioproportion is maintained in carrying out the present invention at thesame proportion as that when no hydrogen sulphide is used.

I claim:

1. A process for the destructive hydrogenation of high boiling-pointhydrocarbons or derivatives thereof which consists in heating thehydrocarbon at a temperature of the order of 440 C. with hydrogen undera pressure of between 110 and 200 atmospheres in the presence of acatalyst mixture comprising molybdenum catalyst and a promoter thereforselected from the group comprising silicon, lithium, boron, phosphorusand calcium, the catalyst and promoter being in peak-ratio proportionsas herein defined together with optimum proportions of a substanceyielding hydrogen sulphide under the conditions of the reaction.

2. A process for the destructive hydrogenation of high boiling-pointhydrocarbons or dep BIA process for the destructive hydrogena tionbofhigh boiling-point hydrocarbons or derivatives thereof which consistsin'heating the hydrocarbon at a temperature .of the order 'of 440 C.with hydrogen under a pressure of the 'order' of 200 atmospheresin thepresence of a catalyst -mixture comprising molybdenum cat- :alyst and apromoter therefor selected from the group comprising silicon, lithium,boron, phosphorus and; calcium, the catalyst and promoter "being inpeak-ratio proportions as herein defined, togetherwith optimumproportions of a substance yielding hydrogen sulphide under theconditions of the reaction.

4. Aprocess for the destructive hydrog enation of high boiling-point,hydrocarbons or derivativesthereof which consists in heating the iconbeing in' peak-ratioproportions as herein defined together with optimumproportions of a substance yielding hydrogen sulphide under 2 5hydrocarbon at a temperature of theorder of 5 440 C; withhydrogen undera pressure of the order of 200 atmospheres wherein the reaction isassisted by a molybdenum catalyst and a silicon promoter therefontheproportion of silicon tomolybdenum being between 5 and 8 per cent 5together with optimum amounts of a substance yielding hydrogen sulphideunder the conditions of the reaction.

6. A process for the destructive hydrogenation of high boiling-pointhydrocarbons or deriv- 40 atives thereof whichconsists in heating thehydrocarbon at a temperature of the order of 440 C. with hydrogen undera pressure of the order of 200 atmospheres wherein the reaction isassisted by a molybdenum catalyst, a silicon 5 50 "I. A process for thedestructive hydrogenation of high boiling-point hydrocarbons orderivatives thereof which consists in heating the hydrocarbon at atemperature of the order of 440 C. with hydrogen under a pressure of theorder 55 of 200 atmospheres wherein the reaction is assisted by amolybdenum catalyst, a lithium promoter therefor the molybdenum andlithium being in peak-ratio proportions as herein defined,

and optimum amounts of a substance yielding 50 hydrogen sulphide underthe conditions of the reaction. i

8. A process for the destructive hydrogenation of high boiling-pointhydrocarbons or derivatives thereof which consists in heating thehydrocar- 65 bon at a temperature of the order of 440 C.-with hydrogenunder a pressure of the order of 200 atmospheres wherein the reaction isassisted by a molybdenum catalyst, a lithium promoter therefor, theproportion of lithium to molybde- 70 num being between land 7.5% andoptimum amounts of a substance yielding hydrogen sulphide under theconditions of the reaction. 7

9. A process for the destructive hydrogenation of high boiling-pointhydrocarbons or deriv mum proportions of a substance yielding hydro- Qti h reof which consistsin heating the hydrocarbon at a temperature ofthe order of 440 C. with hydrogen underfa pressure of the order of 200atmospheres wherein the. reaction is assisted bya molybdenumcata1yst,..a lithium promoter therefor, the ratio of lithium tomolybdenum being between '7 and 7.5%, and 'opti- ,mum proportions ofcarbon bisulphide, as a substance yielding hydrogen sulphide under theconditions of the reaction. a V

-10.;A process for the destructive hydrogenation of high boiling-pointhydrocarbons or derivativesthereof which consists in heating thehydrocarbon at a temperatui'eof the order of 4410 C. with hydrogen undera pressure of the order of .200 atmospheres wherein the reaction.isassisted'by a molybdenum catalyst, a boron promoter therefor themolybdenum and boron being in peak-ratio proportions, and. optimumproportions of, a substance yielding hydrogen sulphide under theconditions of the reaction.

11. A process; for the destructive hydrogenation: of high boiling-pointhydrpcarbons or de-L.

gen sulphide under the cqnditions of the reac-,- tion.

v-12. .A'; process for the destructive; hydrogenation of high-boiling-point hydrocarbons: orgrderivati'ves thereof which consists. inheating. 1th? 5 hydrocarbon at a temperature of the. ordergof 440 -C.with hydrogen-under a pressure otrthe order of 200 atmospheres whereinthe reactiongis assisted by a molybdenum catalyst, ,a, boron .promotertherefor, the proportion ofv boron to (we molybdenumibeing between 7 and10%, andoptie mumproportions.otcarbon bisulphide as a sub-Lstancesyielding hydrogen sulphide under the conditions of the reaction.I

'13.A process for the destructive tion of .high boiling-pointhydrocarbons or ,de-

rivatives thereof which consists in heating {the hydrocarbon at atemperature of the order ,of 440 C. with hydrogenunder a pressureof theorder of 200 atmospheres in the p'resenceof; 1a. catalyst-mixturecomprising a molybdenum ,cat alyst, and a promoter therefor-selectedtromthe group comprising si1icon, -1ithium, boron; phos- 'phorusandoa1c-ium,'the catalyst andpromoter being in peak-ratioproportions ashereinnde- 25 .fined, and a substance yielding ,hydrogen sulphide inamounts-that will yieldunderytheconditions of the reaction, from 3 to 6%of hydrogen sulphide b ased on theamount of hydrocarbon being treated. 7L

' ROLANDHALL GRIFFITH.

hydrogena- I

